This invention relates to an adjustable laser diode lens assembly, and more particularly, to a high precision adjustable collimator assembly used for a large numerical aperture collimating lens or a series of large numerical aperture collimating lenses.
A conventional raster scanner system utilizes a light source, a collimator, a multi-faceted rotating polygon mirror as the scanning element and a photosensitive medium. The light source, which is typically a laser source, emits a light beam and sends it to the collimator. The collimator collimates the light beam and sends it to the rotating polygon mirror. In an overfilled scanning system, the light beam which is wide enough to cover two facets will be directed onto two facets of the rotating polygon mirror. The rotating polygon mirror reflects the light beam and also causes the reflected light to revolve about an axis near the center of rotation of the rotating polygon and scan a line. This reflected light beam can be utilized to impinge upon a photographic film or a photosensitive medium, such as a xerographic drum at the output of the imaging system.
An overfilled raster output scanner enables a high resolution, fast printing rate and wide scan range. However, it requires the light beam to be wide enough to cover two facets of a rotating polygon mirror. Typically, high resolution raster scanning systems require a large rotating polygon mirror with large facets. Therefore, the light beam required to fill two facets of a large rotating polygon mirror has to be adequately wide such as 1 inch.
In order to collimate and widen a light beam from a laser diode to a light beam with a width such as 1 inch or more, a large numerical aperture lens or a series of large numerical aperture lenses are required. Large numerical aperture lenses have large diameters such as 1 inch. Therefore, a housing is required to hold the laser diode and a lens barrel containing one collimating lens or a series of collimating lenses. Since the the assembly of the housing and the lens barrel is quite large, a mechanism is required to move the lens barrel in the housing at a high precision with respect to the diode which is at a fixed position and then fix the lens barrel in the housing at a desired position.
It is an object of this invention to provide an adjustable collimator assembly.